Video: Black Carbon Travels the Globe

SAN FRANCISCO — Black carbon, the soot emitted when fuels like diesel, wood and coal are burned, may have a bigger impact on climate in some areas than greenhouse gases. New research presented here at the American Geophysical Union meeting shows that the 20 percent decrease in the extent of Himalayan glaciers since the 1960s may be partly due to an influx of black carbon from Asian cities.

Using satellite data and computer models, NASA atmospheric scientist William Lau and colleagues put together this animation of Earth’s atmospheric concentration of black carbon from August to November. The time of fastest glacial melting on the western Tibetan Plateau coincides with the highest concentration of black carbon in the area, Lau reported.

“Over areas of the Himalayas, the rate of warming is more than five times faster than warming globally,” Lau said in a press release. “Based on the differences it’s not difficult to conclude that greenhouse gases are not the sole agents of change in this region. There’s a localized phenomenon at play.”

The dark soot particles affect the area by absorbing sunlight and heating the air around them. When black carbon gets trapped in the air flanking the Himalayas, it creates a warm layer that then rises into the mountains and accelerates glacial melting. The effect of this regional phenomenon may even be greater than that of global warming from greenhouse gases.